The 1.2meter dishes (4') really are the mini-buds, and anything smaller should take a different name.
Yes, you can play around with microBUDs, but it's just that == playing around. I managed to get a few signals on a 31" dish with a C-Band LNB (The Word on 91, NHK on 58), but it's a lot of finagling and a ton of luck, along with a the occasional breakup.